1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method having a power saving mode.
2. Description of the Related Art
Some typical image forming apparatuses, such as printers, copiers, and multifunction peripherals (MFP), have a power saving mode (sleep status mode).
The typical image forming apparatus decreases the reception speed of data upon receiving the data in the sleep status mode, and then starts a reception process of the data with the start of an initialization process for returning to a normal status mode. The typical image forming apparatus returns the reception speed to the original speed when the initialization process is completed.
The typical image forming apparatus returns to the normal status mode after moving to the sleep status mode since the initialization process is performed each time the data is received while in the sleep status mode. Therefore, this results in low power saving.
Another image forming apparatus includes an energy saving subsystem having a power consumption that is smaller than that of a main system. To move to the sleep status mode, this other image forming apparatus supplies power to the energy saving subsystem and stops supply of the power to the main system and subsystems (including a print engine, a scanner, and a display panel that are controlled by the main system). The energy saving subsystem in this other image forming apparatus controls the supply of the power to the main system and the subsystems. This other image forming apparatus is better able to suppress power consumption because the power is supplied only to the energy saving subsystem while in the sleep status mode.
However, the energy saving subsystem in this other image forming apparatus supplies power to start the main system upon receiving the data from a host apparatus if this other image forming apparatus is in the sleep status mode. The main system processes the data received from the host apparatus regardless of the kind of the data.
Accordingly, the speed to process the data in the sleep status mode in this other image forming apparatus is much lower than the speed to process the data in the normal status mode by an amount of the time period during which the main system is started.
Meanwhile, the typical image forming apparatus includes a processor and is operated by controlling a program. Specifically, the image forming apparatus includes a non-volatile memory, such as a NAND flash memory, and reads out a controller program stored in the non-volatile memory to execute the read out controller program using the processor.
In the typical image forming apparatus, the controller program is read out from the NAND flash memory to be executed after returning from the sleep status mode in which the processor in the controller is turned off.
Accordingly, if switching between the sleep state mode and the normal status mode frequently occurs, a read disturb error may possibly occur in the controller program.